Guides
Find the cause, not just the symptom
Step-by-step answers using the tools that come with macOS. Each guide ends with how iKnowMyMac does the same thing faster.
- GuideWhy is my Mac slow? How to find the causeMost slow Macs have one of five causes. Here is how to tell which one you have, using Activity Monitor and a few Terminal commands that come with macOS.9 min read
- GuideMac battery drain overnight: how to find the causeA sleeping MacBook should lose very little charge overnight. If yours loses a lot, it either didn't really sleep or kept waking up. macOS logs both, and here is how to read them.9 min read
- GuideActivity Monitor alternatives for Mac: an honest comparisonSix tools that do part of Activity Monitor's job, each better at something. Here is what each is for, what it costs, and which one fits the question you are actually asking.8 min read
- GuideWhat is memory pressure on a Mac?Memory pressure is macOS's own answer to “does this Mac have enough memory right now?” It is a better signal than free memory, and it is the first thing to check when a Mac feels slow.7 min read
- GuideWhat is taking up space on my Mac?When the disk fills up, the usual suspects are a few very large folders you forgot about. Here is how to find them with the tools that come with macOS, and how to remove things so you can still put them back.8 min read
- GuideHow to uninstall a Mac app completelyDragging an app to the Trash removes the app, not the files it created. Here is where those files live, how to find them without removing another app's files by mistake, and how to check for leftover login items.7 min read
- GuideHow to keep your Mac awake during a buildmacOS sleeps an idle Mac even while a long build or download is running in Terminal. `caffeinate`, which comes with macOS, keeps it awake for exactly as long as the task takes.5 min read
- GuideWhat is kernel_task, and why is it using so much CPU?kernel_task is macOS itself. When it sits at the top of Activity Monitor, it's usually doing its job: stopping a hot Mac from getting hotter. Here is how to confirm that and find what's making the heat.7 min read
- GuideWhat is mds_stores, and why is it using so much CPU?mds, mds_stores and mdworker are Spotlight. When they're busy, macOS is building or updating the index that makes searches instant. It's usually temporary, and you can make it smaller.6 min read
- GuideWhat is WindowServer on a Mac?WindowServer puts every window, menu and animation on your screens. When it's busy, it's doing what your apps and your display setup ask of it. Here's how to find out which.8 min read
- GuideWhat is photoanalysisd on a Mac?photoanalysisd and mediaanalysisd are Photos working in the background, scanning your library. They get busy after big changes to your library, and they go quiet when the scan is done.5 min read
- GuideWhat is backupd on a Mac?backupd is Time Machine. When it's busy, a backup is running. Here's how to see what it's doing and how to make backups lighter.6 min read
- GuideHow much memory does Ollama use on a Mac?An Ollama model holds about its download size in memory, plus a context cache, for as long as it stays loaded. Here's how to see the real figure on your Mac, why it's often bigger than the download, and how to give the memory back.8 min read
- GuideWill this model fit on my Mac?A local model fits when its weights plus its context fit in the memory the GPU may use, with room left for your other apps. Here's the arithmetic, estimates for common sizes, and how to find your Mac's own limit.7 min read
- GuideHow to kill leftover dev servers after Claude CodeCoding agents start dev servers to test their work. Usually those stop with the session. When they don't, they keep holding a port and memory until you find them. Here's how to find them and check them before you stop anything.7 min read
- GuideHow to check when Time Machine last backed upTime Machine is quiet when it works and just as quiet when it stops. Here's where to see the last successful backup, what to check when it's old, and how to hear about it next time.5 min read
- GuideHow to use multiple GitHub accounts on one MacTwo GitHub accounts on one Mac means four settings that have to agree: the email you commit with, the SSH key you push with, the GitHub CLI account and the signing key. Here's how to set up each one so work repos act as work and personal repos act as personal.8 min read
- GuideCommitted with the wrong email? How to fix itA commit made with the wrong email is easy to fix while it's only on your Mac, and harder once it's pushed. Here's how to fix one commit or several, what --reset-author and --author each change, and how to make sure it doesn't happen again.7 min read
- GuideHow to switch GitHub accounts with gh auth switchThe GitHub CLI can stay logged in to more than one account on the same host, with one active at a time. Here's how to add a second account, switch between them, and avoid opening a pull request from the wrong one.5 min read
- GuideHow to set a different Git email per folderGit can switch your commit email by folder on its own, with a rule in ~/.gitconfig. Here's the rule, a version that matches by remote instead of folder, and how to check which email a repo will really use.6 min read
- GuideWhat is mediaanalysisd on a Mac?mediaanalysisd is macOS looking through your photos and videos so you can search them, copy text out of them and look up what's in them. It does the work on your Mac, so it shows up as CPU use.4 min read
- GuideMac slow after a macOS update? Here's what's runningA Mac that feels slow right after a macOS update is usually busy, not broken. Several parts of macOS redo their work after an update, and they all run at once.6 min read
- GuideGoogle Chrome Helper using too much memory or CPU on a Mac?Chrome runs every site, extension and the GPU in separate helper processes, so Activity Monitor shows dozens of rows and no total. Here's how to find the tab behind them, decide whether it's actually a problem, and fix it.8 min read
- GuideHow to check USB cable speed on a MacA fast SSD on the wrong cable runs at USB 2 speed, and it looks the same in Finder. Here's how to see the speed each USB or Thunderbolt device is getting, what the figure means, and how to find what's limiting it.7 min read
- GuideWhat is photolibraryd on a Mac?photolibraryd looks after your Photos library: it records every import and edit, and keeps the library in step with iCloud Photos. When it's busy, your library is changing or syncing.5 min read
- GuideWhat is purgeable space on a Mac?Purgeable space is disk space that's in use, but only by things macOS can remove on its own. Your Mac counts it as available, which is why two tools can give two different answers about how much room you have.6 min read
- GuideIs my Mac affected by the eMudhra certificate incident?Your browsers already block the eight eMudhra certificates. The tools that carry their own list of trusted certificates don't, until you update them. Here's which ones, the version that fixes each, and the commands to check.6 min read
- GuidePHP2Shell (CVE-2026-109618 and CVE-2026-109619) on a MacTwo critical flaws in PHP itself can allow remote code execution without logging in. macOS doesn't come with PHP, so if you have it, you installed it. Here's how to find which PHP you run and update it.6 min read
- GuideNode.js October 2026 security release: check and update Node on a MacNode.js 26.12.1, 24.22.1 and 22.23.4 fix ten vulnerabilities. On a Mac, Node can come from half a dozen places, and each one updates differently. Here's how to tell which you have and the exact commands for each.6 min read
- GuideSwitching from Little Snitch or LuLuYour rules come with you. Little Snitch exports them as an .lsrules file and LuLu as a JSON file; iKnowMyMac imports both, and shows what it will do with every rule before it adds any.6 min read
- GuideMac keeps waking up from sleep? Find the wake reasonA sleeping Mac wakes up more often than you'd think, usually for a few seconds with the screen off. macOS writes down every wake and why. Here's how to read it and stop the wakes that cost you battery.7 min read
- GuideHow to see which USB devices were connected to your MacSystem Information shows what's plugged in right now. It can't tell you what was plugged in an hour ago, or while you were away. Here's what macOS does keep, and how to keep the rest.6 min read
- Guide“Background Items Added” on a Mac: what it means and who added itmacOS tells you when an app sets something up to run on its own, but the notification doesn't say much. Here's how to find the item, the app behind it, when it runs and who signed it.7 min read
- GuidePort 5000 or 3000 already in use on a Mac: what's using itYour server won't start because the port is taken, and you didn't start anything on it. On a Mac, port 5000 has a usual suspect, and port 3000 has another. Here's how to tell which, and what to do.5 min read
- GuideIs your React or Next.js project affected by the React Server Components hole?A crafted request can run code on a server that renders React Server Components, before any login. Next.js has its own advisories on top. Here's who is affected, how to check every project on your Mac, and the commands to update.7 min read
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